Disassembling/Assembling Engine
Disassembling and assembling engineTools
Tools and materials
Required special tools
Note: The special tools that are required are described in the chapter (Special) tools required for repairing the M48/00 and M48/50 engines' engines or in the corresponding individual chapters.
Technical values
Note: For information on all tightening torques, see Tightening torques for Cayenne S (M48/00) and Cayenne Turbo (M48/50)' or the corresponding individual chapters.
Preliminary work
Preliminary work for disassembling engine
1. Remove engine.
2. Remove engine from transmission.
Note:
^ The engine must be disassembled in accordance with the detailed descriptions in the Technical Manual!
^ This chapter does not provide details or further information. Further details can be found in the relevant individual descriptions.
3. Secure engine support P 9676 on engine. To do this, use the four screws for mounting elements 9590 and tighten them slightly. Secure engine on engine support. To do this, carefully guide the engine support axle into the take-up bore on the engine support and secure it.
4. Remove wire harness for engine.
5. Remove the generator.
6. Remove power-steering pump.
7. Remove left additional assembly bracket -2- and right engine carrier -8-. There are also two dowel sleeves (not shown) on the additional assembly bracket.
Disassembling engine
1. Remove starter.
2. Remove knock sensors.
3. Remove cylinder heads.
4. Remove water pump.
5. Remove coolant regulator.
6. Remove guide and tensioning rails.
7. Remove crankshaft.
8. Remove oil spray jets on turbo engine and cap on naturally aspirated engine.
Preliminary work
Preliminary work for engine assembly
1. The crankcase must be prepared for installation (dowel sleeves, caps and pins screwed in).
Note:
^ The engine must be disassembled in accordance with the detailed descriptions in the Technical Manual!
^ This chapter does not provide details or further information. Further details can be found in the relevant individual descriptions.
2. Attach top section of crankcase to engine support. To do this, use the four screws for mounting elements 9590 and tighten them slightly.
Assembling engine
ATTENTION Leaks due to components being at too low a temperature or at different temperatures!
^ If components that are cold or at different temperatures are sealed together by the application of sealant, adhesion problems and leaks can arise due to the build-up of condensation water or component distortion.
^ Components must have reached at least 17°C throughout.
^ Components must not be too hot (distortion).
^ Spare parts that are stored in the cold or heat (strong sunlight), must be brought to room temperature or the same temperature as other parts before installation.
Note:
^ The engine must be disassembled in accordance with the detailed descriptions in the Technical Manual!
^ This chapter does not provide details or further information. Further details can be found in the relevant individual descriptions.
Note: Four oil spray nozzle are installed in the M48/50 engine instead of the caps used in the M48/00 engine.
1. Fit caps on crankcase. When doing so, make sure that new O-rings are fitted. Tighten the Tightening torque: 10 (7.5 ft-lb.) Nm.
Note: The bearing shells are available in various tolerance classes. The classes are indicated by the color marking on the outside. The color marking must match the corresponding color dot on the crankshaft.
2. Insert the bearing shells with the lubricating groove into the upper part of the crankcase. Make sure the twist locks are positioned correctly. Then lightly oil the bearing locations.
3. Insert the sickle-shaped washer (make sure of axial bearing play). To do this, insert the two sickle-shaped washers to the left and right on crankshaft bearing no. 3. Apply some grease (000.043.204.17) between the crankshaft bearing and the sickle washers so that the sickle washers do not fall down. Each of the lubricating grooves of the sickle-shaped washers must face outwards.
WARNING The crankshaft is heavy!
^ There is a danger of hands being crushed when inserting the crankshaft.
^ Hold the very outside of the crankshaft.
^ Wear gloves.
4. Insert crankshaft. The connection flange must point towards the back of the engine. Then secure the crankshaft from falling down using holding bridges 9677. Attach the holding bridges at bearing locations 3 and 5 Crankshaft holding bridges. Then screw the fastening screw of the front pulley into the crankshaft until they just make contact.
5. Turn crankcase by 180° on the assembly support.
Note:
^ The pistons must already be pre-fitted (pistons, piston rings, connecting rods and fastening material) before performing the next step.
^ The required bearing shells must be inserted in the connecting rods.
^ The connecting rod is symmetrical and can be fitted either on the piston so that the number on the connecting rod is facing outwards or inwards, or the tolerance class designation of the piston does not have to be on the same side as the connecting rod code. The direction of travel arrow is on the same side as the connecting rod code -A- as is evident on the piston shown. This can be installed as standard on one cylinder bank side on the same side as shown here, and on the other cylinder bank side, the connecting rod code is on the opposite side. The connecting rod code is installed to the exhaust side as standard.
^ When installing the piston in the crankcase, the direction of travel arrow must point in the direction of travel.
^ The code on the connecting-rod big end and connecting-rod bearing cap must be on the same side and at the exhaust side.
6. Install piston. To do this, turn the crankshaft with a wrench (a/f 27) until the corresponding lift pin is pointing straight downwards.
7. Lightly oil cylinder and piston.
8. Align piston-ring set (offset by 120°) and compress piston rings using piston ring restraining strap for 944 - S2 and Boxster and 911 Carrera (996) 57.
9. Place piston onto cylinder from above and push into cylinder. When doing so, make sure that the direction of travel arrow is pointing forwards (in direction of travel). -Arrow-
Sliding in the piston
10. Push the piston downwards until the connecting-rod bearing is sitting on the lift pin. Then fit connecting-rod bearing cap with bearing shell. The connecting rod numbers must face each other. Screw in con-rod bolts by hand. Make sure the twist locks and connecting rod code are positioned correctly during assembly.
11. Fit the opposite piston (e.g. 1 and 4).
12. Fit other pistons in accordance with the step above.
13. Turn crankcase on the assembly support until the crankshaft is on top.
Note: Con-rod bolts must always be replaced.
14. Tighten con-rod bolts that have been replaced.
15. holding bridges 9677 must be removed from the crankshaft.
16. Screw the two thin centering pins 9321 into the outer fastening bores on the upper part of the crankcase -Arrows- (crankshaft not fitted in illustration).
17. Insert the bottom bearing shells into the bottom section of the crankcase (bed plate) and lightly oil running surfaces. Pay attention to the twist locks when doing so.
18. Make sure the crankcase is ready to be screwed in. Check that the sickle discs are positioned correctly. Degrease parting surfaces between top and bottom section of crankcase. A totally grease-free product (e.g. brake cleaner) must be used for this. Then insert a new O-ring at the front of the parting surface.
Note:
^ Liquid sealant must be applied and screws tightened immediately and without interruption.
^ The threads and head contact surface of the bearing seat screws (M10 x 1.5 and M12 x 1.5) must be oiled.
19. Apply Loctite 5970 liquid sealant - 000.043.300.39 (status 11/2005, for details of current sealant, see Parts Catalogue) to the lower part of the crankcase as shown. The surfaces marked -A- must be cleaned after fitting.
20. Place bottom section of crankcase into position. When doing so, make sure that the sealing bead is not destroyed.
21. For details of the tightening sequence for the bottom section of the crankcase and tightening torques.
22. Then tighten the four fastening screws on the clutch side Tightening torque: 23 (17 ft-lb.) Nm -Arrows-.
23. Fit chain drive sprocket on the crankshaft. Unscrew fastening screw on belt pulley. Check that the feather keys are fitted correctly and push on the chain sprocket with the oil pump drive chain. The double-tooth row must be facing forwards.
24. Install oil pump.
25. Fit guide rail -9- and tensioning rail -6- for the oil pump drive. Push the tensioning rail over the fastening pin and engage the guide rail in the bottom section of the crankcase as shown in the illustration.
26. Fit timing chain cover on oil pump. Tighten the Tightening torque: 10 (7.5 ft-lb.) Nm.
27. Turn engine 180° on the assembly support.
28. Install starter.
29. Fit knock sensors. Align the knock sensors as shown in the illustration and tighten the Tightening torque: 23 (17 ft-lb.) Nm.
30. Install thermostat housing. Fit a new O-ring at the water pump inlet and then insert the thermostat housing. Tighten the two Tightening torque: 10 (7.5 ft-lb.) Nm.
31. Mount cylinder heads. To do this, turn the engine on the assembly support so that the required cylinder bank is pointing vertically upwards.
32. Fit new cylinder-head gasket. The gasket designation is shown on the back and is legible from above when fitted correctly.
33. Fit cylinder head. The fastening screws must be tightened in the sequence shown below. The tightening sequences and step-by-step tightening torques must be observed!.
34. Fit camshaft housing. Apply a bead of Loctite 5970 liquid sealant - 000.043.300.39 (status 11/2005, for details of current sealant, see Parts Catalogue) -A- as shown. Then screw two thin centering pins 9321 into two opposing blind holes in the cylinder head. Insert the O-ring -B- into the oil duct. Wipe off any sealant -C- that emerges as a result of screwing.
35. Position camshaft housing and then unscrew the two centering pins.
36. Tighten the camshaft housing screws in the sequence shown. Don't forget the two hexagon socket head bolts at the front of the camshaft housing.
Note:
^ The bearing locations of the camshafts must be lightly oiled.
^ Place the camshafts in such a way that the cams are positioned as shown below!
37. Install camshafts.
38. Fit oil return line to camshaft housing 5 - 8. Fit oil return line -1- with a new O-ring -2-. Tighten the four Tightening torque: 10 (7.5 ft-lb.) Nm -3 and 4- (camshaft housing, cylinder head, crankcase and oil pan).
39. Position oil feed housing of inlet camshaft and tighten Tightening torque: 10 (7.5 ft-lb.) Nm.
Note: If the camshaft timing gears and camshaft adjusters are removed completely, the diamond washers and fastening screws must be replaced!
40. Replace the diamond washer and fastening screw located underneath the camshaft adjuster and camshaft timing gear.
41. Fitting deflection rail.
ATTENTION Damage to the camshaft switch-over valve!
^ Malfunction.
^ Do not turn camshaft switch-over valve.
42. Install camshaft switch-over valves Tightening torque: 10 (7.5 ft-lb.) Nm. Figure Fastening screw for camshaft switch-over valve shows procedure with timing-case cover fitted.
43. Fit timing drive mechanism. Fit guide rail of cylinder bank 5 - 8. Tighten the leaf spring of the oil pump tensioning rail at the same time.
44. Fit tensioning rail to cylinder bank 1 - 4.
45. Install timing chain. Position the chain on the crankshaft gear wheel and then fit it over all four camshaft timing gears. To do this, use both hands to carefully insert the camshaft adjuster and camshaft timing gear into the timing chain. Screw in fastening screws of the timing gears loosely to half a turn. Screw in fastening screws of the timing gears loosely to half a turn.
46. Fit U-rail. Insert the U-rail into the timing drive mechanism from above. Tighten the four fastening screws.
47. Fit the short guide rails between the camshaft timing gears.
48. Fit timing-case cover.
49. Place sealing ring over crankshaft using assembly sleeve.
50. Tighten the two upper fastening screws (M6 x 50) and the lower fastening screws (M6 x 12) by hand.
51. Tighten the two upper fastening screws (M6 x 50) and the lower fastening screws (M6 x 12) by hand. Then tighten the screws crosswise. Tightening torque: 10 (7.5 ft-lb.) Nm
52. Pull assembly sleeve evenly off the sealing ring.
Note:
^ If the sealing flange on the pulley is slightly rusted, polish the rust off with a special polishing pad (e.g. Never Dull).
^ If the sealing flange is badly corroded or contains deep grooves, replace it.
Note:
^ A feather key is inserted into the crankshaft. When fitting the pulley, ensure that the feather key slots into the groove in the pulley.
^ The key must not fall into the engine.
53. Fit crankshaft belt pulley.
54. Fit oil pan.
55. Fit drive plate or flywheel.
56. Install chain tensioner with new sealing ring. Tightening torque: 60 (44 ft-lb.) Nm
Note: To remove the play from the timing chain for the setting process, the crankshaft must be positioned approx. 45° in front of the TDC of cylinder 1 before turning!
57. Set the timing.
58. Install the camshaft housing cover on both cylinder banks.
59. Fit water pump.
Subsequent work
1. Fit left additional assembly bracket -2- and right engine carrier -8-. There are still two dowel sleeves (not shown) on the additional assembly bracket.
Removing and installing engine support
2. Fit power-steering pump.
3. Fit generator.
4. Fit wire harness for engine.
5. Refit engine on transmission.
6. Install engine.